WATER PROPULSION SPEEDS AND POWER OUTPUT BY COMB PLATES OF THE CTENOPHORE PLEUROBRACHIA PILEUS UNDER DIFFERENT CONDITIONS

1993 ◽  
Vol 183 (1) ◽  
pp. 149-164
Author(s):  
D. Barlow ◽  
M. A. Sleigh
Keyword(s):  
Time Delay ◽  
Angular Velocity ◽  
Wave Velocity ◽  
Phase Difference ◽  
Power Output ◽  
Beat Frequency ◽  
Flow Speed ◽  
Metachronal Wave ◽  
Pleurobrachia Pileus ◽  
Recovery Stroke

Parameters of ciliary beating and water propulsion can be studied in a unique fashion in ctenophores because the beat frequency can be controlled. Pleurobrachia pileus comb plates were driven at frequencies between 2 and 25 Hz and at temperatures between 10 and 25°C. As frequency is increased from 5 to 25 Hz, the rest period between beats is first shortened and then disappears: the duration of the effective stroke is reduced because the angular velocity (which is directly proportional to the sliding velocity of the microtubules) and the tip speed of each plate increase whilst the amplitude of the beat remains unchanged. The recovery stroke is shortened because the recovery bend is propagated more quickly to the tip of the plate. The phase difference between adjacent plates in the metachronal wave (expressed as a percentage of the cycle) is increased in spite of a sharp decrease in the time delay between adjacent plates, a reduction in the number of plates per wave and an increase in the metachronal wave velocity. The water flow speed becomes more continuous and increases in approximate proportion to the tip speed whilst the estimated power output of a metachronal wave increases exponentially, from 10–10 W at a tip speed of about 20 mm s-1 to 10-8 W at a tip speed of about 75 mm s-1. When comb plates are driven to beat at 10 Hz and the temperature is raised from 10°C towards 20°C, the duration of the effective stroke is reduced and the comb plates have a somewhat higher angular velocity and tip speed; the duration of the recovery stroke is reduced with a faster propagation of the recovery bend; a rest phase first appears between successive beats and then becomes longer. The phase difference between adjacent plates in a metachronal wave (expressed as a percentage of the cycle time) is decreased, as is the time delay between successive plates in a metachronal wave, so that the number of plates per wave and the wave velocity are increased. The water flow speed and power output are increased by a modest amount (a rise in temperature from 10 to 20°C produces changes equivalent to those produced by a 5 Hz increase in frequency at 20°C). The cooperation between adjacent plates in the antiplectic metachronal wave makes a major contribution to the dramatic increase in power output of each metachronal wave that is seen as the beat frequency is increased.

The Swimming of Nymphon Gracile (Pyconogonida)

1971 ◽  
Vol 55 (1) ◽  
pp. 273-287
Author(s):  
ELFED MORGAN
Keyword(s):  
Angular Velocity ◽  
Hydrodynamic Force ◽  
Beat Frequency ◽  
High Elevation ◽  
Dorsal Side ◽  
Constant Angular Velocity ◽  
Power Stroke ◽  
Lateral Thrust ◽  
Constant Depth ◽  
Recovery Stroke

1. The organization of the swimming legs of N. gracile has been described. The legs beat ventrally so the animal swims with the dorsal side foremost. The joints between the major segments of the leg are extended for most of the power stroke, but the distal segments articulate sequentially later in the beat, commencing with the flexion of the femoro-tibial joint at the end of the power stroke. Continued flexion reduces the leg radius considerably during the recovery stroke. 2. Animals swimming at constant depth were found to have a leg-beat frequency of about 1 beat/s. Above this the rate of ascent increased rapidly with increasing frequency of beat. Abduction or adduction of the leg usually occurred prior to the start of the power stroke with the femur in the elevated position. 3. Assuming a fixed limb profile at constant angular velocity, maximum lift was calculated to have occurred with the femur inclined at an angle of about 50° to the dorso-ventral body axis. The outward component of the lateral thrust decreased to zero at this point, and with further declination of the femur the lateral forces became inwardly directed. Of the different segments of the leg, tibia 2 and the tarsus and propodium contribute most of the hydrodynamic force. 4. The angular velocity of the leg varied during the power stroke, and the actual forces generated during two beats having the same amplitude and angular velocity but of high and low elevation were calculated. Greater lift occurred during the high-elevation beat when the leg continued to provide lift throughout the power stroke, whereas the low-elevation beat acquired negative lift values towards the end of the power stroke. The lateral thrust was now directed entirely inwards.

An Improved Airborne Single Observer Passive Location

2012 ◽  
Vol 157-158 ◽  
pp. 1533-1536
Author(s):  
Yong Wang ◽  
Chang Qiang Huang ◽  
Zheng Wang ◽  
Wang Xi Li
Keyword(s):  
Angular Velocity ◽  
Phase Difference ◽  
Measurement Problem ◽  
Doppler Frequency ◽  
Original Method ◽  
Parameter Measurement ◽  
Frequency Change ◽  
Passive Location ◽  
Change Rate ◽  
Domain Information

Using phase difference change rate’s augmentation to angular velocity, an improved passive location is developed,which solves the high precision parameter measurement problem of angular velocity in passive location and tracking via spatial-frequency domain information. The simulation shows that this method can reduce the difficulties of parameter measurement. The ranging error is mainly affected by the measurement error of phase difference change rate and doppler frequency change rate. Compared with the original method, it has higher passive location precision.

Nature of the mammalian ciliary metachronal wave

1993 ◽  
Vol 75 (1) ◽  
pp. 458-467 ◽  
Author(s):  
L. B. Wong ◽  
I. F. Miller ◽  
D. B. Yeates
Keyword(s):  
Beat Frequency ◽  
Longitudinal Direction ◽  
Longitudinal Axis ◽  
Ciliary Beat Frequency ◽  
Metachronal Wave ◽  
Epithelial Tissues ◽  
Tracheal Epithelial ◽  
The Mean ◽  
Temporal And Spatial ◽  
Ciliary Beat

The temporal and spatial coordination of ciliary beat (metachronicity) is fundamental to effective mucociliary transport. Metachronal wave period (MWP) and ciliary beat frequency (CBF) of fresh excised sheep and canine tracheal epithelial tissues were measured with the use of a newly developed alternating focal spot laser light scattering system. MWP was determined from cross correlation of the heterodyne signals from the alternating focal spots. CBF was determined by autocorrelation of the heterodyne signals from each of the spots. MWP and CBF were measured in four sheep tracheal epithelial tissues with the use of longitudinal interfocal spot distances of 6 and 18 microns. In three canine tracheal epithelial tissues MWP and CBF were measured both longitudinally and circumferentially with interfocal spot distances of 5, 15, 65, 87, and 96 microns. For the sheep tracheal epithelial tissues the mean CBF was 5.9 +/- 0.4 Hz (mean of means; range 3.6 +/- 0.5 to 9.9 +/- 1.5 Hz), whereas the mean MWPs for 6- and 18-microns interfocal spot distances were 0.50 +/- 0.1 and 0.47 +/- 0.1 s, respectively. For the canine tracheal epithelial tissues the mean CBF was 4.0 +/- 0.2 Hz (2.0 +/- 0.8 to 7.2 +/- 3.2 Hz), whereas the mean longitudinal MWP was 1.5 s and the mean circumferential MWP was 2.1 s. Geometric combination of the MWP components leads to a derived MWP of 2.6 s with a propagation direction of 54 degrees with respect to the longitudinal axis of the trachea. MWP was found to be episode modulated with 12- to 20-min intervals in the longitudinal direction, but modulation was not as apparent in the circumferential direction. These data suggest that MWP and CBF are regulated by separate intracellular, intercellular, and intraciliary mechanisms.

scholarly journals GENETIC VARIABILITY OF FLIGHT METABOLISM IN DROSOPHILA MELANOGASTER. I. CHARACTERIZATION OF POWER OUTPUT DURING TETHERED FLIGHT

Genetics ◽  
1981 ◽  
Vol 98 (3) ◽  
pp. 549-564
Author(s):  
James W Curtsinger ◽  
Cathy C Laurie-Ahlberg
Keyword(s):  
Drosophila Melanogaster ◽  
Power Output ◽  
Beat Frequency ◽  
Wing Beat ◽  
Tethered Flight ◽  
Flight Metabolism ◽  
Flight Parameters ◽  
Wing Stroke ◽  
Stroke Amplitude

ABSTRACT The mechanical power imparted to the wings during tethered flight of Drosophila melanogaster is estimated from wing-beat frequency, wing-stroke amplitude and various aspects of wing morphology by applying the steady-state aerodynamics model of insect flight developed by Weis-Fogh (1972, 1973). Wing-beat frequency, the major determinant of power output, is highly correlated with the rate of oxygen consumption. Estimates of power generated during flight should closely reflect rates of ATP production in the flight muscles, since flies do not acquire an oxygen debt or accumulate ATP during flight. In an experiment using 21 chromosome 2 substitution lines, lines were a significant source of variation for all flight parameters measured. Broadsense heritabilities ranged from 0.16 for wing-stroke amplitude to 0.44 for inertial power. The variation among lines is not explained by variation in total body size (i.e., live weight). Line differences in flight parameters are robust with respect to age, ambient temperature and duration of flight. These results indicate that characterization of the power output during tethered flight will provide a sensitive experimental system for detecting the physiological effects of variation in the structure or quantity of the enzymes involved in flight metabolism.

Effects of longitudinal body position and swimming speed on mechanical power of deep red muscle from skipjack tuna (Katsuwonus pelamis)

2002 ◽  
Vol 205 (2) ◽  
pp. 189-200
Author(s):  
Douglas A. Syme ◽  
Robert E. Shadwick
Keyword(s):  
Swimming Speed ◽  
Power Output ◽  
Beat Frequency ◽  
Mechanical Power ◽  
Skipjack Tuna ◽  
Cycle Frequency ◽  
Katsuwonus Pelamis ◽  
Red Muscle ◽  
Tail Beat ◽  
Work Loop

SUMMARY The mechanical power output of deep, red muscle from skipjack tuna (Katsuwonus pelamis) was studied to investigate (i) whether this muscle generates maximum power during cruise swimming, (ii) how the differences in strain experienced by red muscle at different axial body locations affect its performance and (iii) how swimming speed affects muscle work and power output. Red muscle was isolated from approximately mid-way through the deep wedge that lies next to the backbone; anterior (0.44 fork lengths, ANT) and posterior (0.70 fork lengths, POST) samples were studied. Work and power were measured at 25°C using the work loop technique. Stimulus phases and durations and muscle strains (±5.5 % in ANT and ±8 % in POST locations) experienced during cruise swimming at different speeds were obtained from previous studies and used during work loop recordings. In addition, stimulus conditions that maximized work were determined. The stimulus durations and phases yielding maximum work decreased with increasing cycle frequency (analogous to tail-beat frequency), were the same at both axial locations and were almost identical to those used by the fish during swimming, indicating that the muscle produces near-maximal work under most conditions in swimming fish. While muscle in the posterior region undergoes larger strain and thus produces more mass-specific power than muscle in the anterior region, when the longitudinal distribution of red muscle mass is considered, the anterior muscles appear to contribute approximately 40 % more total power. Mechanical work per length cycle was maximal at a cycle frequency of 2–3 Hz, dropping to near zero at 15 Hz and by 20–50 % at 1 Hz. Mechanical power was maximal at a cycle frequency of 5 Hz, dropping to near zero at 15 Hz. These fish typically cruise with tail-beat frequencies of 2.8–5.2 Hz, frequencies at which power from cyclic contractions of deep red muscles was 75–100 % maximal. At any given frequency over this range, power using stimulation conditions recorded from swimming fish averaged 93.4±1.65 % at ANT locations and 88.6±2.08 % at POST locations (means ± s.e.m., N=3–6) of the maximum using optimized conditions. When cycle frequency was held constant (4 Hz) and strain amplitude was increased, work and power increased similarly in muscles from both sample sites; work and power increased 2.5-fold when strain was elevated from ±2 to ±5.5 %, but increased by only approximately 12 % when strain was raised further from ±5.5 to ±8 %. Taken together, these data suggest that red muscle fibres along the entire body are used in a similar fashion to produce near-maximal mechanical power for propulsion during normal cruise swimming. Modelling suggests that the tail-beat frequency at which power is maximal (5 Hz) is very close to that used at the predicted maximum aerobic swimming speed (5.8 Hz) in these fish.

WATER FLOWS AROUND THE COMB PLATES OF THE CTENOPHORE PLEUROBRACHIA PLOTTED BY COMPUTER: A MODEL SYSTEM FOR STUDYING PROPULSION BY ANTIPLECTIC METACHRONISM

1993 ◽  
Vol 177 (1) ◽  
pp. 113-128 ◽  
Author(s):  
D. Barlow ◽  
M. A. Sleigh ◽  
R. J. White
Keyword(s):  
Computer Program ◽  
Water Flow ◽  
High Speed ◽  
Beat Frequency ◽  
Longitudinal Axis ◽  
Model System ◽  
The Other ◽  
Contour Maps ◽  
Water Flows ◽  
Pleurobrachia Pileus

Patterns of water flow around steadily beating comb plates of Pleurobrachia pileus were tracked using suspended plastic beads. The positions of the beads and the comb plates in the plane of the central longitudinal axis of the comb row were digitised from high-speed cine films covering several beat cycles. All of the data from each sequence were combined using a computer program which integrated them into a standard cycle, and the resulting data were plotted by a second computer program to produce charts for different stages in the beat cycle showing the flow velocity at a grid of points. On these charts, contour maps were drawn to indicate the speed and direction of the water flow. Water is drawn towards each comb row from ahead and from the sides and accelerates strongly backwards in a fairly narrow stream which joins those from the other seven comb rows at the rear of the animal. At a beat frequency of 10 Hz the comb plates move with a tip speed of up to 70 mm s-1 in their effective stroke; they have an estimated Reynolds number of 9 in this stroke. Changes in inter- plate volume between adjacent antiplectically coordinated plates are very important in propulsion, particularly near the end of the effective stroke when pairs of adjacent plates close together and cause the high-speed water from around the ciliary tips to be shed into the overlying stream as a series of jets at speeds of 50 mm s-1 or more. The antiplectic coordination of the comb plates makes a major contribution to the efficiency of propulsion.

scholarly journals Deep phenotyping, including quantitative ciliary beating parameters, and extensive genotyping in primary ciliary dyskinesia

2019 ◽  
Vol 57 (4) ◽  
pp. 237-244 ◽  
Author(s):  
Sylvain Blanchon ◽  
Marie Legendre ◽  
Mathieu Bottier ◽  
Aline Tamalet ◽  
Guy Montantin ◽  
...  
Keyword(s):  
Primary Ciliary Dyskinesia ◽  
High Speed ◽  
Genetic Disorder ◽  
Beat Frequency ◽  
Ciliary Beat Frequency ◽  
Central Complex ◽  
Ciliary Beating ◽  
Recovery Stroke ◽  
Biallelic Mutations ◽  
Ciliary Dyskinesia

BackgroundPrimary ciliary dyskinesia (PCD) is a rare genetic disorder resulting in abnormal ciliary motility/structure, extremely heterogeneous at genetic and ultrastructural levels. We aimed, in light of extensive genotyping, to identify specific and quantitative ciliary beating anomalies, according to the ultrastructural phenotype.MethodsWe prospectively included 75 patients with PCD exhibiting the main five ultrastructural phenotypes (n=15/group), screened all corresponding PCD genes and measured quantitative beating parameters by high-speed video-microscopy (HSV).ResultsSixty-eight (91%) patients carried biallelic mutations. Combined outer/inner dynein arms (ODA/IDA) defect induces total ciliary immotility, regardless of the gene involved. ODA defect induces a residual beating with dramatically low ciliary beat frequency (CBF) related to increased recovery stroke and pause durations, especially in case of DNAI1 mutations. IDA defect with microtubular disorganisation induces a low percentage of beating cilia with decreased beating angle and, in case of CCDC39 mutations, a relatively conserved mean CBF with a high maximal CBF. Central complex defect induces nearly normal beating parameters, regardless of the gene involved, and a gyrating motion in a minority of ciliated edges, especially in case of RSPH1 mutations. PCD with normal ultrastructure exhibits heterogeneous HSV values, but mostly an increased CBF with an extremely high maximal CBF.ConclusionQuantitative HSV analysis in PCD objectives beating anomalies associated with specific ciliary ultrastructures and genotypes. It represents a promising approach to guide the molecular analyses towards the best candidate gene(s) to be analysed or to assess the pathogenicity of the numerous sequence variants identified by next-generation-sequencing.

Effect of input signal type and time delay in sensors on wave velocity in rock specimens

2019 ◽  
Vol 260 ◽  
pp. 105225 ◽  
Author(s):  
Jin-Yeon Kim ◽  
Jaewon Jang ◽  
Tae Sup Yun
Keyword(s):  
Time Delay ◽  
Wave Velocity ◽  
Input Signal ◽  
Signal Type ◽  
Rock Specimens

scholarly journals Frequency of Maximal Power Output at in vivo Myofilament Lattice Spacing Matches Drosophila Wing Beat Frequency

2011 ◽  
Vol 100 (3) ◽  
pp. 12a
Author(s):  
Bertrand C.W. Tanner ◽  
Gerrie P. Farman ◽  
Thomas C. Irving ◽  
David W. Maughan ◽  
Mark S. Miller
Keyword(s):  
Power Output ◽  
Lattice Spacing ◽  
Beat Frequency ◽  
Wing Beat ◽  
Maximal Power ◽  
Maximal Power Output ◽  
Wing Beat Frequency ◽  
Drosophila Wing

High Speed PIV Measurement of Impinging Flow on a Horizontal Axis Wind Turbine

2012 ◽  
Author(s):  
J. Stephen Hu ◽  
Jian Sheng ◽  
Michele Guala ◽  
Leonardo Chamorro
Keyword(s):  
Boundary Layer ◽  
Angular Velocity ◽  
Wind Turbine ◽  
Power Output ◽  
High Speed ◽  
Large Scale ◽  
Flow Structures ◽  
Flow Conditions ◽  
Horizontal Axis Wind Turbine ◽  
Impinging Flow

The focus of this paper is to characterize the upstream wake of a three bladed Horizontal Axis Wind Turbine (HAWT) and its interaction with the native structures within a turbulent boundary layer (TBL). The overarching question is the most prevailing length and time scales of coherent structures that would interact with a HAWT and how they would be affected. The implications include wall flow and structure interaction and flow induced noise generation in large scale turbo machineries. The experiments are performed on a turbine that has a 0.128 m rotor diameter, a hub height of 0.104 m and a tip speed ratio of 4. The HAWT model is placed in a large scale wind tunnel in a boundary layer with a thickness δ of ∼0.6 m. The boundary layer is generated by a 60 mm picket fence trip and developed over a smooth wall under thermally neutral conditions. Measurements are performed under ReD of 4 × 105 and 6 × 105. Both turbine geometries and flow conditions are scaled from operating conditions in the field. High speed Particle Image Velocimetry (PIV), turbine voltage output, and angular velocity measurements are conducted simultaneously, by which one could relate the upwind flow structures with the power output of the turbine. High speed PIV offer details in spatial and temporal characteristics of the impinging flow structures, whilst the voltage anemometer and tachometer provide instantaneous measurement of angular velocity of the turbine. PIV measurements are taken at a rate of 1500 image pairs per second with a 100 μs delay between laser pulses. Each sample area is 0.15 × 0.15 cm. Two locations up to two rotor diameters upwind are measured. Instantaneous voltage is taken at a sampling rate of 30 kHz and a sampling time of 60s to ensure sufficient temporal resolution and coverage. Ongoing analysis using conditional averaging based on extreme power output events will provide insights in assessing a HAWT performance in unsteady flow conditions.

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